Cooling device for pneumatic tools



w. F. ZIMMERMANN COQLING DEVICE FOR PNEUMATIC TOOLS Filed Sept, 6. 1925N VE N TOR. 117272111112 I! 1121.222 0291101111 #15 AT RNEK.

Patented July 27, 1925.

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WILLIAM FRANK ZIMMERMANN, OF WAVERLY, NEW YOBIZ, ASSIGNOR TO INGEESOLL-RAND COMPANY, OF JERSEY CITY, JERSEY, A CORPORATION OF NEW JERSEY.

COOLING DEVICE FORPNEUMATIC TOOLS.

Application fi led September 16, 1925. Serial No. 56,612.

This invention relates to pneumatic tools, but more particularly to acooling device for riveting hammers and the like, having a cylinder, areciprocating piston, which constitutes the hammer, and a fluid actuateddistributing valve.

The objects of the invention in particular are to secure means forcooling the forward end of the cylinder or barrel by conducting thewhole or a portion of the exhaust fluid through passages in the forwardend of the barrel and thence rearwardly to a rearward exhaust port. r i

The cooling of the barrel, and especially the front end of the barrel,is particularly desirable with pneumatic hammers of the shorter lengthswhich are more frequently used for such service, as car fabrication, inwhich rivets of standard sizes are driven rapidly in succession so thatthe heat from the rivet is transmittedthrough the rivet set to thebarrel and. thence up the barrel. This transmission ofheat forces thehammer operator to gradually withdraw the hand away from the forward endofthe bar,- rel, resulting in the disadvantage thatthe riveting hammeris more difiicult to'guide and hold properly while the rivet is beingdriven. v y I If the exhaustfluid is. discharged through the forward endof the barrel immediately around thevrivet set, any scale loosenedduringthe riveting hasa tendency to be blown into the operators face andone of the'objects of this invention is to avoid this disadvantage andyet obtain the desired cooling effects around the shank of the rivet setor other impact nnplement and throughout the barrel. Either the entireexhaust fluid or only a portion of the exhaust fluid, as desired, may beby-passed through the wall of the barrel and thence through a passagearound the forward end of the barrel and thence rearwardly to theusualexhaustport. One of the advantages of by-passing only a portion of theexhaust fluid, as indicated, resides in the fact thatsuch by-pass may bemore conveniently applied to existingriveting hammers without change inthe valve perating mechanism,

The invention hown in one of its prefered formsin theaccompanyingdrawings, in which 7 Figure 1 is a longitudinal sectionalside view, partly broken away, of a riveting hammer having the inventionappliedthereto, and f Figure 2 is a similar view showing the piston andthe valve in a different position.

A The type of pneumatichammer selected for illustration of the inventionis like that described in U. S. Patent No. 1,528,781, grantechlt-larch10., 1925 to Gaid H. Peck and is in all respects like the said pneumatichammer including the same distributing valve, but halvingthe presentcooling means incorporated in the pneumatic hammer.

'Referring to the drawings of the present application, the pneumatichammer comprises the cylinder A having a bore B in which the hammerpiston C is adapted to reciprocate and impart blows of impact to a rivetset D or other tool removably held within a forward. end of the cylinderas by means of the rivet set clip E of any suitable character. Asuitable handle F secured to the cylinder as by means of the bolts Gforms the back head of the machine and pressure fluid from the inlet Hcontrolled by a hand operated valve (not shown) 0011- so nected to beoperated by the lever J, is supplied to the machine through the mainsupply passage K.

In this instance a valve block L and a cap piece 0 fitted together forma valve casing, removably held within the rearward end of the cylinderby the handle or back head F.

A hollow cylindricalrfluid actuated differential distributing valve P.in all respects like the valve shown in said Patent No. 1,528,? 81 andfunctioning in the same manner, is slidable longitudinally wlthin thevalve casing in axial alignment with the cylinder A and is formed with abore Q slightly larger than the bore of the cylinder, to permit thepiston C to pass through the valve on its rearward stroke. In thisinstance the valve P controls the admission and exhaust of motive fluidfrom both ends of the cylinder by means of suitable ports 10o andpassages in the cylinder, the head block L and the cap piece 0, only somuch of the distribution features and ports and passages for operatingsaid valve being shown as will indicate the type of valve sincethe valveitself forms no part of this. invention.

The neck V of the valve, located forwardly of the head T, is forcontrolling the supply to the forward end of "the cylinder through thecombined supply and. exhaust passage TV in the cylinder communicatingwith the forward end of the cylinder through the port- X, and this neckV is also for controlling the exhaust from both ends of the cylinderthrough the exhaust passage Y preferably protected by a suitable exhaustdeflector Z.

As the piston travels forwardly, as indicated in Figure 2, with thevalve in forward position. the forward end of the cylinder may exhaustthrough the port X, passage lV, port 6 in the cap piece O, communicatingwith the groove in the cappiece 0 around the valve neck V and from saidgroove 7 through the )ort g in the cap piece to atmosphere" throng theexhaust passage Y. As the iston travels rearwardly, as indicated inigure 1, with the valve in rearward position, fluid is exhausted fromthe rearward end of the cylinder directly through the port and theexhaust port Y to atmosphere.

An additional groove 3 is formed in the cap piece'O forwardly of thegroove 7 connecting the port g with an additional port 4 in the cappiece. A passage 5 in the cylinder wall affords comunication for exhaustfluid between the port 41 and a port 6 in the forward end of thecylinder at a point be yond the cylinder port X to permit exhaustfluidto surround the shank of the rivet set D. A groove 7 at this pointconnects the port 6 with an opposite port 8 in thecylinder, which port 8is connected by the cylinder passage 9 with the atmospheric exhaust portY.

The ports and passages described and numbered from 3 to 9 inclusive,form a by pass for exhaust fluid through which the exhaust fluid isconducted from a point at the rearward end of the cylinder forwardlythrough one ortion of the cylinder wall, thence througi a passage 7around the forward end of the cylinder and rearwardly to the atmosphericexhaust ort Y through another portion of the cy inder wall for coolingthe cylinder and the shank of the rivet set orot'her impact element.

It will be observed that the passage or groove in the cap piece O of thevalve casing or cage is always opened to exhaust in either forward orrearward position of the valve P so that the by-pass described functionsfor cooling purposes both on the forward and rearward stroke of thepiston.

Obviously by closing comunication between the groove 3 and the port y inthe cap piece 0 by means of a Jlug or otherwise. the entire exhaustcoulc be directed first to the forward end of the cylinder and thencarried rearwardly to the exhaust port Y. if desired. The cooling meansdisclosed operates satisfactorily and well and has been found toaccomplish the objects sought.

No special provision is necessary for inducing the flow of exhaus airthrough the bypass around the rivet set. other than the naturalrestriction of the exhaust through the groove 3 and small ports and -land the provision of the usual exhaust deflector of ordinaryconstruction. The restriction of the exhaust at port leading moredirectly to atmosphere is about the same as the restriction at the portl leading loss di rcctly to atmosphere, and as the deflector acts as abattle. also retarding or choking the flow, the exhaust air has twopaths. and some of the air will take the more direct path and some willtake the less direct path. depending on the amount of resistance to flowat the restricted ports g and at and in the exhaust passages.

I claim 1. In a pneumatic hammer, the combination of a cylinder, areciprocating piston, a distributing valve, an atmospheric exhaust portfor the cylinder at the rearward end of the cylinder. and means forpermitting the exhaust fluid to flow from a point at the rearward end ofthe cylinder forwardly through one portion of the cylinder wall. thencethrough a passage around the forward end of the cylinder and thenrearwardly to said atmospheric exhaustport through another portion ofthe wall, for cooling the cylinder.

2. In a pneumatic hammer, the combination of a cylinder, a reciprocatingpiston, 11 distributing valve. an atmospheric exhaust port for thecylinder at the rearward end of the cylinder, and means for by-passing aportion of the exhaust fluid from a. point at the rearward end of thecylinder for wardly through one portion of the cylinder wall, thencethrough a passage around the forward end of the cylinder and thenrearwardly to said atmospheric exhaust port through another portion ofthe wall, for cooling the cylinder.

3. In a pneumatic hammer, the cou'ihiuation of a cylinder, areciprocating piston a distributing valve, an atmospheric exhaust portfor the cylinder at the rearward end of the cylinder. exhaust passagesleading from said atmospheric exhaust port to and from the forward endof the cylinder wall, and a passage in the cylinder wall connecting theforward ends of said exhaust passages and encircling that portion of thecylinder wall into which the shank of the impact implement is adapted toextend, whereby the cylinder and the shank of said implement are cooledby said exhaust fluid.

4. In a pneumatic hammer, the combination of a cylinder, a reciprocatingpiston, a distributing valve controlling both the inlet and exhaust fromboth ends of the cylinder, an atmospheric exhaust port for the cylinderat the rearward end of the cylinder, and means for permitting theexhaust fluid to flow from a pointat the rearward end of the cylinderforwardly through one portion of the cylinder wall, thence through apassage around the forward end of the cylinder and then rearWardly tosaid atmospheric exhaust port through another portion of the wall, forcooling the cylinder.

5. In a pneumatic hammer, the combination of a cylinder, a reciprocatingpiston, a distributing valve controlling both the inlet and exhaust fromboth ends of the cylinder, an atmospheric exhaust port for the cylinderat the rearward end of the cylinder, and means for by-passing a portionof the exhaust fluid from a point at the rearward end pheric exhaustport through another por- 2.

tion of the wall, for cooling the cylinder.

6. In a pneumatic hammer, the combinatlon of a cylinder, a reciprocatingpiston, a

distributing valve controlling both the inlet and exhaust from both endsof the cylinder, an atmospheric exhaust port for the cylinder at therearward end of the cylinder, exhaust passages leading from said exhaustport to and from the forward end of the cylinder Wall, and a passage inthe cylinder wall connecting the forward ends of said exhaust passagesand encircling that portion of the cylinder wall into which the shank ofthe impact implement is adapted to extend, whereby the cylinder and theshank of Eaioli implement are cooled by said exhaust In testimonywhereof I have signed this specification.

VILLIAM FRANK ZIMMERMANN.

